This invention relates to a method and apparatus for skein dyeing which avoids chevron patterns in fabrics made from the skein dyed yarns.
Chevroning in fabrics such as knitted cloth and tufted carpets results from the color contrast dyeing of the yarns used in the fabrics. Such patterning is an undesirable characteristic and is difficult to hide, especially in uniform pile height fabrics and more particularly when a low pile height is required, as in many cut pile (such as plush) or loop pile carpets. While warp printing avoids chevroning, this form of color contrast dyeing does not provide the versatility, clarity, uniformity and fastness of coloration permitted by skein dyeing. In addition, skein dyeing promotes deeper dye penetration since it is based on exhaust dyeing and may be combined with autoclave heat setting to lower processing costs.
Accordingly, an object of the invention is to provide improvements in skein dyeing apparatus so that yarns can be dyed thereby, which yarns do not promote undesirable chevroning in fabrics made therefrom. This and other objects, features and advantages will be apparent from the following description.
In brief outline, the foregoing objects are achieved by asymmetric skein color contrast dyeing of skeins, that is, by a color contrast dyeing technique wherein the color contrast repeat length is greater on the average than the circumference of the yarn in the skein. As a result the color repeat length along yarn unwound from the skein is not regular and this is reflected in the higher degree of random coloration in fabrics made from the yarns required for non-chevroning. In skein dyed yarns which cause chevroning the skein is dyed symmetrically, that is, the color repeat length on the average is the same as the skein circumference and the unwound yarn exhibits regularity of color repeat length.
The asymmetric skein dyeing method of the invention is embodied in the simple but surprisingly efficient step of applying a color contrast dye to less than the entire width, horizontally, of a skein, while the skein is held stationary in a vertical plane. Preferably, less than half the width of the skein is dyed in this manner, such as results from impingement of dye from two or three closely positioned holes in a dye tube placed horizontally and adjacent an exterior side of a skein. The dye thereby impregnates a discrete portion of the skein which is less than its width horizontally, with the result that when the skein is unwound, it will be found that the color repeat length on the average is greater than the length corresponding to the skein circumference. Random coloration is thus introduced along the yarn length, thereby eliminating the chevron patterning in fabrics made from the yarn, which would result had the coloration been regular along the yarn length. The method of the invention also permits non-chevroning skein dyeing of yarn in a plurality of colors, starting with an overall base color and followed by sequential dyeing with two to four, or more, contrast colors.
The method, apparatus and products of the invention are significant improvements over the prior art as represented by U.S. Pat. Nos. 2,043,870 and 3,541,635. Although the skein dyeing in these patents is termed "random," the randomness appears to relate only to height of the dyeing (also known as "dip length") on vertically positioned skeins. The dyeing is across the entire width of the skein and therefore is not asymmetric and will not provide the non-chevroning of the invention.